Velocity of liquid hydrocarbon fuels in a pipeline can not be measured by magnetic flowmeters, because their __________ is very low/small.
A. Thermal conductivity
B. Electrical conductivity
C. Specific gravity
D. Electrical resistivity
Answer: Option B
Solution (By Examveda Team)
Magnetic flowmeters work on the principle of electromagnetic induction.This means they rely on the liquid being measured to have some electrical conductivity.
Here's a simplified explanation:
Imagine the liquid flowing through a pipe surrounded by a magnetic field.
If the liquid is electrically conductive, its moving through this field generates a small voltage.
The flowmeter measures this voltage and relates it to the flow rate.
Liquid hydrocarbon fuels (like gasoline or kerosene) are typically poor conductors of electricity.
In other words, their electrical conductivity is very low.
Therefore, if you try to use a magnetic flowmeter on a liquid hydrocarbon fuel, the signal generated will be too weak or nonexistent, making an accurate measurement impossible.
Let's look at why the other options are less likely to be correct:
Option A: Thermal conductivity: How well a substance conducts heat, while important in some applications, doesn't directly impact the operation of a magnetic flowmeter.
Option C: Specific gravity: This is the ratio of the density of a substance to the density of water. While it relates to the fluid properties, it's not the primary factor affecting measurement in this type of flowmeter.
Option D: Electrical resistivity: This is the opposite of electrical conductivity (how much a substance resists electrical current). While related, the more direct factor influencing the flowmeter's operation is the conductivity itself - whether it's high enough to generate a measurable signal.
This Question Belongs to Chemical Engineering >> Fluid Mechanics
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Comments (3)
A. Thermal conductivity
B. Electrical conductivity
C. Specific gravity
D. Electrical resistivity
A. $$\frac{{\text{V}}}{{{{\text{V}}_{\max }}}} = {\left( {\frac{{\text{x}}}{{\text{r}}}} \right)^{\frac{1}{7}}}$$
B. $$\frac{{\text{V}}}{{{{\text{V}}_{\max }}}} = {\left( {\frac{{\text{r}}}{{\text{x}}}} \right)^{\frac{1}{7}}}$$
C. $$\frac{{\text{V}}}{{{{\text{V}}_{\max }}}} = {\left( {{\text{x}} \times {\text{r}}} \right)^{\frac{1}{7}}}$$
D. None of these
A. d
B. $$\frac{1}{{\text{d}}}$$
C. $$\sigma $$
D. $$\frac{l}{\sigma }$$
A. $$\frac{{4\pi {\text{g}}}}{3}$$
B. $$\frac{{0.01\pi {\text{gH}}}}{4}$$
C. $$\frac{{0.01\pi {\text{gH}}}}{8}$$
D. $$\frac{{0.04\pi {\text{gH}}}}{3}$$
The wrong statement is:
C. Streamlines intersect at isolated point of zero velocity and infinite velocity
π Explanation:
Letβs evaluate each option one by one:
A. It is always parallel to the main direction of the fluid flow
β Correct
A streamline is tangent to the velocity vector of the fluid at every point.
So, the fluid flows along the streamline, and it is always aligned with the local flow direction.
B. It is a line across which there is no flow and it is equivalent to a rigid boundary
β Correct
In ideal flow (especially inviscid or irrotational flow), no fluid crosses a streamline.
Hence, it can be treated like a slip surface or boundary.
C. Streamlines intersect at isolated point of zero velocity and infinite velocity
β Wrong Statement
Streamlines can never intersect. If they did, a single point would have two different velocity directions, which is physically impossible.
At stagnation points (where velocity is zero), streamlines approach but do not intersect.
Also, infinite velocity is non-physical in real fluid flow.
D. The fluid lying between any two streamlines can be considered to be in isolation and the streamline spacing varies inversely as the velocity
β Correct
This is the concept of a streamtube.
Due to continuity, if streamlines are closer together, velocity is higher, and vice versa.
β Final Answer (Wrong Statement):
C. Streamlines intersect at isolated point of zero velocity and infinite velocity
What Is relation b/w velocity and electical conductivity
Why answer B